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  Subjects -> ENGINEERING (Total: 1963 journals)
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ENGINEERING (1120 journals)            First | 5 6 7 8 9 10 11 12 | Last

Matériaux & Techniques     Full-text available via subscription   (Followers: 1)
Mathematical Models and Methods in Applied Sciences     Hybrid Journal   (Followers: 2)
Mathematical Problems in Engineering     Open Access   (Followers: 3)
Mathematics of Control, Signals, and Systems (MCSS)     Hybrid Journal   (Followers: 3)
Mauerwerk     Hybrid Journal  
Measurement     Hybrid Journal   (Followers: 1)
Measurement Science Review     Open Access   (Followers: 1)
Meccanica     Hybrid Journal   (Followers: 1)
Mechatronics     Hybrid Journal   (Followers: 4)
Medical and Biological Engineering and Computing     Hybrid Journal   (Followers: 2)
Medical Engineering & Physics     Hybrid Journal   (Followers: 9)
Membrane Science and Technology     Full-text available via subscription   (Followers: 2)
Membrane Technology     Full-text available via subscription   (Followers: 1)
Memetic Computing     Hybrid Journal  
Metal Powder Report     Full-text available via subscription   (Followers: 2)
Metallurgist     Hybrid Journal   (Followers: 2)
Metaphysica     Hybrid Journal   (Followers: 1)
Metascience     Hybrid Journal   (Followers: 1)
Metrologia     Full-text available via subscription   (Followers: 1)
Microelectronic Engineering     Hybrid Journal   (Followers: 4)
Microelectronics International     Hybrid Journal  
Microelectronics Journal     Hybrid Journal   (Followers: 3)
Microelectronics Reliability     Hybrid Journal   (Followers: 6)
Microfluidics and Nanofluidics     Hybrid Journal   (Followers: 9)
Micromachines     Open Access   (Followers: 1)
MNASSA : Monthly Notes of the Astronomical Society of South Africa     Full-text available via subscription   (Followers: 1)
Modelling and Simulation in Engineering     Open Access   (Followers: 4)
Modern Applied Science     Open Access   (Followers: 1)
Molecular BioSystems     Full-text available via subscription   (Followers: 1)
Molecular Engineering     Hybrid Journal  
Molecular Pharmaceutics     Full-text available via subscription   (Followers: 8)
MRS Bulletin     Full-text available via subscription   (Followers: 5)
MRS Online Proceedings     Full-text available via subscription   (Followers: 1)
Multiagent and Grid Systems     Hybrid Journal  
Multidimensional Systems and Signal Processing     Hybrid Journal  
NANO     Hybrid Journal   (Followers: 6)
Nano Letters     Full-text available via subscription   (Followers: 40)
Nano Research     Hybrid Journal   (Followers: 3)
Nano Reviews     Open Access   (Followers: 15)
Nanopages     Full-text available via subscription   (Followers: 1)
Nanoscale and Microscale Thermophysical Engineering     Hybrid Journal   (Followers: 3)
Nanoscale Systems : Mathematical Modeling, Theory and Applications     Open Access  
Nanotechnologies in Russia     Hybrid Journal   (Followers: 1)
Nanotechnology     Hybrid Journal   (Followers: 9)
Nanotechnology Magazine, IEEE     Full-text available via subscription   (Followers: 12)
Nanotechnology Reviews     Full-text available via subscription   (Followers: 4)
Natural Hazards     Hybrid Journal   (Followers: 179)
Nature Nanotechnology     Full-text available via subscription   (Followers: 44)
Naval Engineers Journal     Hybrid Journal   (Followers: 3)
NDT & E International     Hybrid Journal   (Followers: 10)
Nexo Revista Científica     Open Access  
Nigerian Journal of Technological Research     Full-text available via subscription  
Nigerian Journal of Technology     Full-text available via subscription  
NIR news     Full-text available via subscription  
Nonlinear Dynamics     Hybrid Journal   (Followers: 5)
Nonlinear Engineering : Modeling and Application     Full-text available via subscription   (Followers: 1)
Nonlinearity     Full-text available via subscription   (Followers: 2)
Nova Scientia     Open Access  
NTM Zeitschrift für Geschichte der Wissenschaften, Technik und Medizin     Hybrid Journal   (Followers: 4)
Nuclear Engineering and Design     Hybrid Journal   (Followers: 11)
Numerical Algorithms     Hybrid Journal   (Followers: 2)
Numerical Heat Transfer, Part A: Applications: An International Journal of Computation and Methodology     Hybrid Journal   (Followers: 5)
Numerical Heat Transfer, Part B: Fundamentals: An International Journal of Computation and Methodology     Hybrid Journal   (Followers: 7)
Ocean Science Journal     Hybrid Journal   (Followers: 3)
Oil and Gas Journal     Full-text available via subscription   (Followers: 10)
Online Journal for Global Engineering Education     Open Access  
Open Journal of Fluid Dynamics     Open Access   (Followers: 3)
Open Journal of Safety Science and Technology     Open Access   (Followers: 2)
Operations Research Letters     Hybrid Journal   (Followers: 4)
Optical Communications and Networking, IEEE/OSA Journal of     Hybrid Journal   (Followers: 3)
Optimization and Engineering     Hybrid Journal   (Followers: 2)
Opto-Electronics Review     Hybrid Journal   (Followers: 1)
OR Spectrum     Hybrid Journal  
Organic Electronics     Hybrid Journal   (Followers: 3)
Ozone Science & Engineering     Hybrid Journal   (Followers: 1)
Papers In Regional Science     Hybrid Journal   (Followers: 6)
Particle & Particle Systems Characterization     Hybrid Journal  
Particulate Science and Technology: An International Journal     Hybrid Journal   (Followers: 1)
Perspectives on Science     Hybrid Journal   (Followers: 4)
Pesquisa Operacional     Open Access  
Pest Management Science     Hybrid Journal   (Followers: 4)
Petroleum Science     Full-text available via subscription   (Followers: 2)
Phase Transitions: A Multinational Journal     Hybrid Journal  
Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences     Full-text available via subscription   (Followers: 5)
Physica B: Condensed Matter     Hybrid Journal   (Followers: 4)
Physica C: Superconductivity     Hybrid Journal  
Physica D: Nonlinear Phenomena     Hybrid Journal   (Followers: 3)
Physics of Fluids     Hybrid Journal   (Followers: 22)
Planning News     Full-text available via subscription   (Followers: 3)
Plasma Devices and Operations     Hybrid Journal   (Followers: 3)
Plasma Science and Technology     Full-text available via subscription   (Followers: 2)
Plasmonics     Hybrid Journal  
Platinum Metals Review     Open Access   (Followers: 2)
Polar Research     Open Access   (Followers: 1)
Polar Science     Hybrid Journal   (Followers: 3)
Polímeros: Ciência e Tecnologia     Open Access   (Followers: 1)
Polish Maritime Research     Open Access  
Polymer Engineering & Science     Hybrid Journal   (Followers: 13)
Polymer International     Hybrid Journal   (Followers: 2)
Polymer Science Series A     Hybrid Journal   (Followers: 3)

  First | 5 6 7 8 9 10 11 12 | Last

Journal Cover Reactive and Functional Polymers
   [6 followers]  Follow    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
     ISSN (Print) 1381-5148
     Published by Elsevier Homepage  [2563 journals]   [SJR: 0.834]   [H-I: 55]
  • Editors and Editorial Board
    • Abstract: Publication date: August 2014
      Source:Reactive and Functional Polymers, Volume 81




      PubDate: 2014-06-18T16:38:55Z
       
  • Poly(β,L-malic acid)/Doxorubicin ionic complex: A pH-dependent
           delivery system
    • Abstract: Publication date: August 2014
      Source:Reactive and Functional Polymers, Volume 81
      Author(s): Alberto Lanz-Landázuri , Antxon Martínez de Ilarduya , Montserrat García-Alvarez , Sebastián Muñoz-Guerra
      Poly(β,L-malic acid) (PMLA) was made to interact with the cationic anticancer drug Doxorubicin (DOX) in aqueous solution to form ionic complexes with different compositions and an efficiency near to 100%. The PMLA/DOX complexes were characterized by spectroscopy, thermal analysis, and scanning electron microscopy. According to their composition, the PMLA/DOX complexes spontaneously self-assembled into spherical micro or nanoparticles with negative surface charge. Hydrolytic degradation of PMLA/DOX complexes took place by cleavage of the main chain ester bond and simultaneous release of the drug. In vitro drug release studies revealed that DOX delivery from the complexes was favored by acidic pH and high ionic strength.


      PubDate: 2014-06-18T16:38:55Z
       
  • A method for preparing water soluble cyclic polymers
    • Abstract: Publication date: July 2014
      Source:Reactive and Functional Polymers, Volume 80
      Author(s): Shiyu Long , Qingquan Tang , Ying Wu , Luoxin Wang , Ke Zhang , Yongming Chen
      A novel ring-closure method was developed to specifically focus on the preparation of water soluble cyclic polymers. The well-defined linear polymers were synthesized by a standard RAFT polymerization using a functional RAFT agent 1. The cyclic polymers were then obtained by virtue of an efficient bromomaleimide-thiol substitution reaction to ring-close the linear precursors. This technique is unique in that it not only produces various well-defined water soluble cyclic polymers with high efficiency and topology purity, but also employs the environmentally benign solvent, water, as the ring-closure reaction media.


      PubDate: 2014-06-18T16:38:55Z
       
  • Cyclodepolymerization as a method for the synthesis of macrocyclic
           oligomers
    • Abstract: Publication date: July 2014
      Source:Reactive and Functional Polymers, Volume 80
      Author(s): Philip Hodge
      Macrocyclic oligomers (MCOs) are important as starting materials for Entropically-driven Ring-opening Polymerizations (ED-ROPs). This article reviews the preparation of MCOs by the cyclodepolymerization (CDP) of condensation polymers. Many MCOs have been prepared successfully this way and in numerous cases individual macrocycles have been isolated. This approach can provide one-step syntheses of many macrocycles. The combination of CDP plus ED-ROP is an attractive potential method for recycling (‘Ring-chain Recycling’) many condensation polymers.


      PubDate: 2014-06-18T16:38:55Z
       
  • Polymerization of styrene and cyclization to macrocyclic polystyrene in a
           one-pot, two-step sequence
    • Abstract: Publication date: July 2014
      Source:Reactive and Functional Polymers, Volume 80
      Author(s): Elizabeth M. Carnicom , Eric S. Tillman
      Dibrominated polystyrene (BrPStBr) was produced by atom transfer radical polymerization (ATRP) at 80°C, using the bifunctional initiator benzal bromide to afford the telechelic precursor. The ATRP reaction was stopped around 40% monomer conversion and directly converted into an radical trap-assisted atom transfer radical coupling (RTA-ATRC) reaction by lowering the temperature to 50°C, and adding the radical trap 2-methyl-2-nitrosopropane (MNP) along with additional catalyst, reducing agent, and ligand to match ATRC-type reaction conditions. In an attempt to induce intramolecular coupling, rather than solely intermolecular coupling and elongation, the total reaction volume was increased by the addition of varying amounts of THF. Cyclization, along with intermolecular coupling and elongation, occurred in all cases, with the extent of ring closure a function of the total reaction volume. The cyclic portion of the coupled product was found to have a 〈G〉 value around 0.8 by GPC analysis, consistent with the reduction in hydrodynamic volume of a cyclic polymer compared to its linear analog. Analysis of the sequence by 1H NMR confirmed that propagation was suppressed nearly completely during the RTA-ATRC phase, with percent monomer conversion remaining constant after the ATRP phase.


      PubDate: 2014-06-18T16:38:55Z
       
  • Editors and Editorial Board
    • Abstract: Publication date: July 2014
      Source:Reactive and Functional Polymers, Volume 80




      PubDate: 2014-06-18T16:38:55Z
       
  • Synthesis of core-fluorescent four-armed star and dicyclic 8-shaped
           poly(THF)s by electrostatic self-assembly and covalent fixation
           (ESA–CF) protocol
    • Abstract: Publication date: July 2014
      Source:Reactive and Functional Polymers, Volume 80
      Author(s): Susumu Fujiwara , Takuya Yamamoto , Yasuyuki Tezuka , Satoshi Habuchi
      A pair of four-armed star and dicyclic 8-shaped poly(tetrahydrofuran)s, poly(THF)s, possessing a perylene diimide group at the core position (Ia and Ib, respectively) were synthesized by means of an electrostatic self-assembly and covalent fixation (ESA–CF) protocol. Mono- and bifunctional poly(THF)s having N-phenylpiperidinium salt end groups accompanying a perylene diimide tetracarboxylate as a counteranion were prepared by the ion-exchange reaction, and the subsequent covalent conversion by reflux in toluene afforded the corresponding core-fluorescent four-armed star and dicyclic 8-shaped poly(THF)s, (Ia and Ib, respectively) for the use of single-molecule fluorescence microscopy measurements.


      PubDate: 2014-06-18T16:38:55Z
       
  • Synthesis of high performance organic–inorganic composite via click
           coupling of block polymer and polyhedral oligomeric silsesquioxane
    • Abstract: Publication date: August 2014
      Source:Reactive and Functional Polymers, Volume 81
      Author(s): Santosh Kumar Yadav , Sibdas Singha Mahapatra , Hee Jeong Ryu , Hye Jin Yoo , Jae Whan Cho
      Novel hybrid systems based on poly(styrene-b-(ethylene-co-butylene)-b-styrene) (SEBS) and a polyhedral oligomeric silsesquioxane (POSS) have been synthesized via click chemistry. Different compositions of SEBS-functionalized POSS were obtained from the reaction of azide-functionalized styrene units of SEBS with alkyne-functionalized POSS molecules. Characterization of SEBS-functionalized POSS by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and nuclear magnetic resonance spectroscopy revealed that the POSS molecules were successfully attached to the phenyl group of the SEBS polymer chain following the click reaction. Homogeneous dispersion of POSS molecules in the polymer matrix was demonstrated by scanning electron microscopy. The POSS molecule showed excellent compatibility with polymer matrix, and as a consequence the remarkable enhancement of mechanical properties (breaking stress=44%, modulus=285%) and thermal stability for the resulting composite films was achieved. The reinforcing effect is ascribed to both the compatible homogeneous dispersion of POSS in the matrix and the covalent bond between SEBS and POSS molecules arising from the click coupling.
      Graphical abstract image Highlights

      PubDate: 2014-06-18T16:38:55Z
       
  • Dual-sensitive and folate-conjugated mixed polymeric micelles for
           controlled and targeted drug delivery
    • Abstract: Publication date: August 2014
      Source:Reactive and Functional Polymers, Volume 81
      Author(s): Wen-Chung Wu , Chi-Ming Huang , Po-Wen Liao
      For this study, we prepared a new type of drug carrier with the characteristics of stimuli-responsive transition and tumor-specific recognition through the co-assembly of two series of amphiphilic block copolymers, poly(ε-caprolactone)-b-poly[triethylene glycol methacrylate-co-N-methacryloyl caproic acid] and poly(ε-caprolactone)-b-poly[triethylene glycol methacrylate-co-N-(2-(methacrylamido)ethyl) folatic amide]. The pH-dependent thermal transition and the content of the targeting ligands of the mixed polymeric micelles are well correlated with the chemical structures and compositions of these two copolymers. Doxorubicin-loaded mixed polymeric micelles are stable at body temperature in the neutral condition for prolonged circulation in blood vessels, and demonstrated rapid drug release at acidic pH levels. The cumulative drug release profiles showed a relatively slow release at pH 7.4, and a quick release of 85% in 3h at pH 5.3. The cytotoxicity tests against FA-positive (HeLa) and FA-negative (HT-29) tumor cell lines suggest that this mixed polymeric micelle system has potential merits as a controlled and targeted drug delivery system.


      PubDate: 2014-06-18T16:38:55Z
       
  • Immobilization of 3-hydroxybenzoate 6-hydroxylase onto functionalized
           electrospun polycaprolactone ultrafine fibers: A novel heterogeneous
           catalyst
    • Abstract: Publication date: September 2014
      Source:Reactive and Functional Polymers, Volume 82
      Author(s): Tiyaporn Srisook , Thammasit Vongsetskul , Jeerus Sucharitakul , Pimchai Chaiyen , Pramuan Tangboriboonrat
      3-Hydroxybenzoate 6-hydroxylase (3HB6H), an enzyme that catalyzes regiospecific para-hydroxylation of aromatic compounds, was successfully immobilized onto electrospun polycaprolactone (PCL) ultrafine fibers (424±99nm in diameter). The fibers were fabricated from 13% w/w PCL (MW ∼8×104 g/mol) dissolved in a mixed solvent of formic acid (25% v/v) and acetic acid (75% v/v) at an applied voltage of 16kV and a fiber collection distance of 12.5cm. Before being immobilized with 3HB6H, the surface of electrospun PCL fibers was functionalized by reacting with ethylenediamine activated with 5% v/v glutaraldehyde using aluminum sulfate as a catalyst. Effects of the immobilization process on pH tolerance and thermal stability of 3HB6H were investigated. Results indicated that 3HB6H immobilized onto PCL fibers could tolerate the changes in temperature and pH better than the free enzyme could. Therefore, the 3HB6H-immobilized PCL fibers are potentially useful as a heterogeneous catalyst under the conditions in which free 3HB6H could not endure.


      PubDate: 2014-06-18T16:38:55Z
       
  • Synthesis and investigation of monomodal hydroxy-functionalized PEG
           methacrylate based copolymers with high polymerization degrees.
           Modification by “grafting from”
    • Abstract: Publication date: September 2014
      Source:Reactive and Functional Polymers, Volume 82
      Author(s): Paulina Maksym-Bębenek , Tadeusz Biela , Dorota Neugebauer
      The synthesis of monomodal copolymers with poly(ethylene glycol) (PEG) side chains from commercial poly(ethylene glycol) methacrylates (PEGMA) by atom transfer radical polymerization (ATRP) is verified. Two hydroxy-functionalized PEGMA macromonomers (520g/mol and 360g/mol) were copolymerized with methyl methacrylate (MMA) using various initial feed (1.5/98.5–50/50mol.%). The copolymers P(MMA-co-PEGMA) with high degree of polymerization, e.g. 100–275 of repeating units in the backbone including 7–56 PEG side chains, were obtained. The relative reactivity ratios of PEGMA and MMA determined by the Jaacks method indicated slightly faster incorporation of macromonomer into polymeric chain than MMA (r MMA =0.79; r PEGMA =1.27). The polymers containing at least 17mol.% of PEGMA units were water-soluble and exhibited clouding point at temperature in a broad range of 39–70°C. The temperature-sensitive effect makes these polymers as a potential carriers in drug delivery systems. In the case of copolymers insoluble in water, a three-step procedure, including esterification to ATRP multifunctional macroinitiators, ATRP of tert-butyl methacrylate (tBMA) by grafting from, deprotection of carboxylic groups by removing tert-butyl groups, was applied to extend PEG grafts and expand the content of hydrophilic fraction (32–94mol.%), what efficiently developed polymer solubility in polar solvents giving possibility for the future biomedical applications.
      Graphical abstract image Highlights

      PubDate: 2014-06-18T16:38:55Z
       
  • The role of polarizability in determining metal ion affinities in
           polymer-supported reagents: Phosphorylated ethylene glycol
    • Abstract: Publication date: August 2014
      Source:Reactive and Functional Polymers, Volume 81
      Author(s): Xiaoping Zhu , Spiro D. Alexandratos
      This is the first of a series of reports that probes the polarizabilities of different immobilized ligands in order to build toward a rational design of ion-selective polymer-supported reagents. In this report, the polarizabilities of four ligands on a polystyrene backbone (phosphorylated ethylene glycol (pEG1), ethylene glycol (EG1), sulfonic acid, and dimethylamine (DMA)) are evaluated with Au(III) and Eu(III) as representative of soft and hard ions, respectively. Interactions are followed by the extent of sorption, the effect of acid concentration, band shifts in FTIR spectra, and Langmuir plots. The phosphoryl oxygen, hydroxyl OH, and amine show an affinity of Au(III)>Eu(III) while Eu(III)>Au(III) is evident with the sulfonic acid. The PO stretching frequency shifts from 1263 to 1249cm−1 upon Au(III) binding. The affinities indicate that oxygen can be considered soft and hard, depending on its microenvironment: neutral oxygen is soft while anionic oxygen may be classified as hard. Though Eu(III) prefers ionic binding with a strong acid ligand, it is also capable of weak binding with a neutral oxygen donor at pH 3 and 4. Sorption is affected by solution acidity despite the absence of ion exchange. Three routes to enhancing ion–interactions thus emerge: preparing single-site ligands whose polarizability matches the targeted metal ion, preparing ligands with multiple binding sites each of which bind weakly on their own, and preparing single-site ligands with dual ion exchange/coordination character.


      PubDate: 2014-06-18T16:38:55Z
       
  • Synthesis and characterization of PS-b-PGMA diblock copolymer and its
           interaction with blood proteins and donepezil
    • Abstract: Publication date: September 2014
      Source:Reactive and Functional Polymers, Volume 82
      Author(s): Leman Buzoglu , Esra Maltas , Mustafa Ersoz , Salih Yildiz
      Biocompatible polystyrene-block-poly(glycidyl methacrylate) (PS-b-PGMA) diblock copolymers with different molecular weights were synthesized via atom transfer radical polymerization (ATRP), homopolymers of styrene with narrow molecular weight distribution were prepared and used macroinitiators for block copolymerization. The effect of time, temperature, solvent, and in-feed ratio on the synthesis of the polymer was examined. Human serum albumin (HSA), bovine serum albumin (BSA), globulin (Glb) and hemoglobin (Hb) which are intrinsically fluorescent blood proteins were interacted with the synthesized PS-b-PGMA diblock copolymers. A calibration curve equation was used to calculate the amount of immobilized proteins on the diblock copolymers through fluorescence spectroscopy. These occurred at wavelengths of 280nm and 324nm, which correspond to the excitation and emission wavelengths of tyrosine and tryptophan residues. Following the interaction of PS-b-PGMA diblock copolymer with the blood proteins, the protein was subjected to a pharmaceutical active substance, donepezil. The copolymers, homo polymers and protein-polymers along with the drug interactions were characterized using 1H NMR, FT-IR and gel permeation chromatography (GPC), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX).
      Graphical abstract image Highlights

      PubDate: 2014-06-18T16:38:55Z
       
  • The adsorptive extraction of oxidized sulfur-containing compounds from
           fuels by using molecularly imprinted chitosan materials
    • Abstract: Publication date: August 2014
      Source:Reactive and Functional Polymers, Volume 81
      Author(s): Adeniyi S. Ogunlaja , Matthew J. Coombes , Nelson Torto , Zenixole R. Tshentu
      An innovative approach for desulfurisation of fuels is proposed. It relies on the formation of recognition sites, complementary to oxidized sulfur-containing compounds, on cross-linked chitosan microspheres and electrospun chitosan nanofibers using the molecularly imprinted polymer technique. Benzothiophene sulfone (BTO2), dibenzothiophene sulfone (DBTO2) and 4,6-dimethyldibenzothiophene sulfone (4,6-DMDBTO2) were used as templates for the preparation of molecularly imprinted polymers (MIPs). The possible molecular interactions between imprinted chitosan adsorbent and oxidized sulfur-containing compounds were investigated by molecular modeling using density functional theory (DFT) and results indicated that interactions took place via hydrogen bonding. The molecularly imprinted polymer adsorbents (cross-linked microspheres and electrospun nanofibers) gave better selectivity for the target sulfonated compounds and the adsorption isothermal studies followed the Freundlich model. Maximum adsorption capacities of 8.5±0.6mg/g, 7.0±0.5mg/g and 6.6±0.7mg/g were observed for model BTO2, DBTO2 and 4,6-DMDBTO2 respectively at 1mL/h when imprinted nanofibers were employed, and the imprinted microspheres gave maximum adsorption capacity of 4.9±0.5mg/g, 4.2±0.7mg/g and 3.9±0.6mg/g for BTO2, DBTO2 and 4,6-DMDBTO2 respectively. Application of the nanofibers to oxidized hydro-treated fuel under continuous flow adsorption system at 1mL/h indicated that 84% of sulfur was adsorbed, with adsorption capacity of 2.2±0.2mg/g.


      PubDate: 2014-06-18T16:38:55Z
       
  • Synthesis of Poly(N-isopropylacrylamide)-b-Poly(ε-caprolactone) and
           Its Inclusion Compound of β -Cyclodextrin
    • Abstract: Publication date: Available online 23 May 2014
      Source:Reactive and Functional Polymers
      Author(s): Zhongyu Duan , Li Zhang , Huili Wang , Bing Han , Binyuan Liu , Il Kim
      Well-defined amphiphilic poly(N-isopropylacrylamide)-b-Poly(ε-caprolactone) (PNIPAM-b-PCL) block copolymers have been successfully prepared in two steps. PNIPAM−OH is firstly prepared by using 4,4’-azobis(4-cyano-1-pentanol) as bifunctional initiator, and then PNIPAM-b-PCL copolymer is synthesized via a ring-opening polymerization of CL using PNIPAM−OH as a macro-initiator in the presence of stannous octoate as a catalyst. The PNIPAM-b-PCL copolymers self-assemble to form spherical micelles of 50-130 nm in diameter, which can be modulated by the chain length of PCL block. The inclusion complexes are fabricated by treating PNIPAM-b-PCL with β-cyclodextrin and they are characterized by infrared and 1H NMR spectroscopies, x-ray powder diffraction, thermogravimetric analysis, and differential scanning calorimetry.
      Graphical abstract image Highlights

      PubDate: 2014-06-18T16:38:55Z
       
  • Synthesis and Properties of Soluble Cross-linkable Fluorinated
           Co-polyimides
    • Abstract: Publication date: Available online 12 June 2014
      Source:Reactive and Functional Polymers
      Author(s): Hongyan Yao , Yunhe Zhang , Kaiyuan You , Yu Liu , Ying Song , Shanyou Liu , Shaowei Guan
      A series of high molecular weight soluble fluorinated cross-linkable co-polyimides (Co-PIs) were synthesized from 1,3-bis(2-trifluoromethyl-4-aminophenoxy)-5-(2,3,4,5-tetrafluorophenoxy) benzene (6FTFPB), 1,4-bis(4-amino-2-trifluoromethylphenoxy)benzene (6FAPB), 1,4-bis(4-amino-2-trifluoromethyl-phenoxy)-2-(3’-trifluoro-methylphenyl)benzene (m-3F-6FAPB) and 4,4’-(hexafluoroisopropylidene)diphthalic anhydride (6FDA). The weight-average molecular weights (Mws) and polydispersities of the co-polyimides were in the range 5.53-7.24 and 1.71-2.04, respectively. By adjusting the feed ratio of diamines, the refractive indices of Co-PIs films were exactly tuned in the range of 1.5203-1.5574 at 633 nm. The co-polyimides showed outstanding solubility in organic solvents and high thermal stability (5% thermal weight-loss temperature beyond 525 °C). Meanwhile, the films had excellent mechanical properties with high tensile strength of 100-108 MPa, Young’s modulus of 3.3-4.2 GPa and elongations at break of 8-15%. Polymers in the form of cast and spun films could be cross-linked by thermal curing at 260 °C. After curing, the Co-PIs films showed excellent chemical resistance, high glass transition temperatures above 270 °C, higher mechanical properties and thermal stability (5% thermal weight-loss temperature beyond 540 °C) and low dielectric constant in the range of 2.37-2.70.


      PubDate: 2014-06-18T16:38:55Z
       
  • Synthesis of polysaccharide derivatives bearing bromobenzoate pendants for
           use as chiral auxiliaries
    • Abstract: Publication date: Available online 13 June 2014
      Source:Reactive and Functional Polymers
      Author(s): Tomoyuki Ikai , Kazuma Kimura , Katsuhiro Maeda , Shigeyoshi Kanoh
      Cellulose and amylose derivatives bearing bromobenzoate pendants were synthesized as chiral auxiliaries to create optically active biaryl compounds through Suzuki–Miyaura cross-coupling with naphthalen-1-ylboronic acids. The regioselectively substituted polysaccharide derivatives bearing 2-bromobenzoate pendants at the 6-position of the glucose unit exhibited higher diastereoselectivity than did the corresponding monosaccharide-based chiral auxiliary and the non-regioselectively substituted polysaccharide derivative bearing 2-bromobenzoates at the 2,3,6-positions. These results suggest that the chiral induction by the regioselectively substituted polysaccharide-based auxiliaries is mainly based on regular higher-order structures, such as one-handed helical structures.


      PubDate: 2014-06-18T16:38:55Z
       
  • Synthesis of Novel Copper Ion-Selective Material Based on Hierarchically
           
    • Abstract: Publication date: Available online 14 June 2014
      Source:Reactive and Functional Polymers
      Author(s): Talitha Oliveira Germiniano , Marcela Zanetti Corazza , Mariana Gava Segatelli , Emerson Schwingel Ribeiro , Maria Josefa Santos Yabe , Evgeny Galunin , César Ricardo Teixeira Tarley
      A novel hierarchically imprinted cross-linked poly(acrylamide-co-ethylene glycol dimethacrylate) using a double-imprinting approach for the Cu2+ selective separation from aqueous medium was prepared. In the imprinting process, both Cu2+ ions and surfactant micelles (cetyltrimethylammonium bromide - CTAB) were employed as templates. The hierarchically imprinted organic polymer named (IIP-CTAB), single-imprinted (IIP-no CTAB) and non-imprinted (NIP-CTAB and NIP-no CTAB) polymers were characterized by SEM, FTIR, TG, elemental analysis and textural data from BET (Brunauer–Emmett–Teller) and BJH (Barrett-Joyner-Halenda). Compared to these materials, IIP-CTAB showed higher selectivity, specific surface area and adsorption capacity towards Cu2+ ions. Good selectivity for Cu2+ was obtained for the Cu2+/Cd2+, Cu2+/Zn2+ Cu2+/Co2+ systems when IIP-CTAB was compared to the single-imprinted (IIP-no CTAB) and non double-imprinted polymer (NIP-CTAB), thereby confirming the improvement in the polymer selectivity due to double-imprinting effect. For adsorption kinetic data, the best fit was provided with the pseudo-second-order model for the four materials, thereby indicating the chemical nature of the Cu2+ adsorption process. Cu2+ adsorption under equilibrium was found to follow dual-site Langmuir-Freundlich model isotherm, thus suggesting the existence of adsorption sites with low and high binding energy on the adsorbent surface. From column experiments 600 adsorption-desorption cycles using 1.8 mol L-1 HNO3 as eluent confirmed the great recoverability of adsorbent. The synthesis approach here investigated has been found to be very attractive for the designing of organic ion imprinted polymer and can be expanded to the other polymers to improve performance of ion imprinted polymers in the field of solid phase extraction.


      PubDate: 2014-06-18T16:38:55Z
       
  • Atom Transfer Radical Polymerization of Glycidyl Methacrylate Followed by
           Amination on the Surface of Monodispersed Highly Crosslinked Polymer
           Microspheres and the Study of Cation Adsorption
    • Abstract: Publication date: Available online 18 June 2014
      Source:Reactive and Functional Polymers
      Author(s): Lisha Wang , Fengcai Li , Minde Yao , Tian Qiu , Weihua Jiang , Li-Juan Fan
      The introduction of reactive groups on the surface of monodispersed highly crosslinked poly(styrene-divinylbenzene) (PSDVB) microspheres was accomplished in two steps. The first step requires immobilizing the initiating groups by a Friedel-Craft acylation between 2-chloropropionyl chlorides and the phenyl groups on the spheres. The second step requires the atom transfer radical polymerization (ATRP) of glycidyl methacrylate (GMA) to obtain spheres (PSDVB-g-PGMA) with epoxy groups on the surface. To demonstrate the feasibility of introducing functionality, the epoxy groups were ring-opened by ethylenediamines, resulting in spheres with amino functionality (PSDVB-g-PGMAEDA). The final spheres were found to have an adsorption capacity of 0.66 mmol/g in the Cu2+ adsorption experiments, as a preliminary application study.
      Graphical abstract image Highlights

      PubDate: 2014-06-18T16:38:55Z
       
  • Nucleation, crystallization, self-nucleation and thermal fractionation of
           cyclic and linear poly(ε-caprolactone)s
    • Abstract: Publication date: July 2014
      Source:Reactive and Functional Polymers, Volume 80
      Author(s): R.A. Pérez , M.E. Córdova , J.V. López , J.N. Hoskins , B. Zhang , S.M. Grayson , A.J. Müller
      A series of low polydispersity cyclic PCL samples (C-PCLs), as well as their linear analogs (L-PCLs), were synthesized by click chemistry in a number average molecular weight (Mn ) range of 2–22kg/mol. They were investigated by Polarized Light Optical Microscopy (PLOM) and Differential Scanning Calorimetry (DSC). The nucleation and overall crystallization kinetics were studied, as well as their self-nucleation behavior and SSA (Successive Self-nucleation and Annealing) thermal fractionation. Cyclic PCLs were found to nucleate and crystallize faster than linear PCLs due to: (a) faster diffusion of C-PCL chains and (b) larger supercoolings of C-PCLs at any given crystallization temperature, as compared to L-PCLs. A bell shape curve was obtained when the overall crystallization rate was examined as a function of Mn , this effect is probably due to a competition between nucleation and diffusion. It was found for the first time, that since cyclic molecules have lower entanglement densities, they can quickly recover their pseudo-equilibrium compact coil conformations upon melting and therefore exhibit much smaller crystalline memory effects than their linear counterparts of identical chain lengths. SSA revealed that C-PCLs are more sensitive to annealing than L-PCLs because their ring topology and limited lamellar chain folding facilitates crystal thickening.


      PubDate: 2014-06-18T16:38:55Z
       
  • Self-diffusion in asymmetric ring-linear blends
    • Abstract: Publication date: July 2014
      Source:Reactive and Functional Polymers, Volume 80
      Author(s): Steven F. Henke , Sachin Shanbhag
      We use the bond-fluctuation model to measure self-diffusivity of asymmetric blends of cyclic and linear polymers, where the number of monomers in the cyclic and linear polymer are different. We consider two series of asymmetric blends and vary the relative composition. In particular, N C = 300 and N L = 150 , and N C = 150 and N L = 300 , where N C and N L are the number of monomers in the cyclic and linear polymers, respectively. Compared to cyclic polymers, the self-diffusivity of linear polymers is relatively insensitive to the blend composition, and is approximately within a factor of two of the pure linear self-diffusivity. In sharp contrast, the self-diffusivity of cyclic polymers exhibits a strong “order of magnitude” variation with the blend microenvironment. The latter data appear to be consistent with trends expected from previous simulations of symmetric cyclic-linear blends, as a function of the fraction of linear polymer.


      PubDate: 2014-06-18T16:38:55Z
       
  • Optically active amino acid-based polyacetylenes: Effect of tunable
           helical conformation on infrared emissivity property
    • Abstract: Publication date: September 2014
      Source:Reactive and Functional Polymers, Volume 82
      Author(s): Xiaohai Bu , Yuming Zhou , Zhenjie Chen , Man He , Tao Zhang
      Chiral amino acid-based monosubstituted acetylene monomers [N-tert-butoxy-carbonyl-l-phenylalanine-N′-propargylamide (LP), and N-tert-butoxycarbonyl-l-serine-N′-propargylamide (LS)] were (co)polymerized with rhodium zwitterion catalyst in THF to afford helical polyacetylenes (PAs) with moderate molecular weights (4400–14,800) in good yields. The optically active PA copolymers were soluble in common organic solvents and proven to adopt predominately single-handed helical conformations according to their intense Cotton effect and large specific rotations. Various contents of amino acid units in side chains facilitated controllable helical secondary structure while the helix was primarily stabilized by hydrogen bonding and steric repulsion between the substituents. Intramolecular hydrogen bonds constructed between hydroxyl and amide groups, in particular, played a significant role in adjusting the helicity and orderliness of the helix. The infrared emissivity values of the PAs at wavelength of 8–14μm were measured and the correlation between helical conformations and their effect on infrared emission were systematically investigated. The results showed that more well-ordered and compact screw-sense could enhance the performance of organic polymers in lowering their infrared emissivity. Among all the as-prepared PAs, poly(LP50-co-LS50) exhibited the lowest infrared emissivity value (ε 25 =0.632) and possessed excellent resistance against heat.
      Graphical abstract image Highlights

      PubDate: 2014-06-18T16:38:55Z
       
  • One-pot synthesis of TBTA-functionalized coordinating polymers
    • Abstract: Publication date: September 2014
      Source:Reactive and Functional Polymers, Volume 82
      Author(s): Alireza Movahedi , Kasper Moth-Poulsen , Johnas Eklöf , Magnus Nydén , Nina Kann
      A one-pot method for the functionalization of polyvinylbenzyl chloride with a tris-(benzyltriazolylmethyl)amine (TBTA) ligand via the copper-catalyzed azide–alkyne cycloaddition reaction (CuAAC) is reported, where the ligand is constructed simultaneously with its attachment to the polymer backbone. A hydrophobic TBTA polymer as well as co-polymers containing TBTA ligands were also prepared to demonstrate the possibility of tailoring the properties of the polymers. The polymers were characterized with FT-IR and NMR spectroscopy, elemental analysis, contact angle measurement, differential scanning calorimetry and thermal gravimetric analysis. The metal coordinating properties of films prepared from the polymers was also demonstrated using X-ray photoelectron spectroscopy and their structures inspected by scanning electron microscopy.


      PubDate: 2014-06-18T16:38:55Z
       
  • Preparation and chemical properties of π-conjugated
           poly(1,10-phenanthroline-3,8-diyl)s with crown ether subunits
    • Abstract: Publication date: September 2014
      Source:Reactive and Functional Polymers, Volume 82
      Author(s): Hiroki Fukumoto , Yumiko Kase , Take-aki Koizumi , Takakazu Yamamoto
      π-Conjugated polymers consisting of 1,10-phenanthroline units and crown ether subunits (Poly-1, Poly-2, and Poly-3) were prepared by dehalogenation polycondensation of the corresponding dibromo monomers using a zero-valent nickel complex as a condensing agent. They were characterized by elemental analysis, 1H NMR and UV–Vis spectroscopies, and cyclic voltammetry (CV). They were partly soluble in CHCl3, and the number average molecular weight of the soluble part of Poly-2, which had 15-crown-5 subunits, was estimated to be 5300. The polymers exhibited UV–Vis peaks at approximately λ max =360nm, which was reasonable. Complexation with [Ru(bpy)2]2+ and alkaline metal ions made the polymer soluble in organic solvents. The complexation of [Ru(bpy)2]2+ to the 1,10-phenanthroline unit proceeded quantitatively, and the [Ru(bpy)2]2+ complexes exhibited CV curves characteristic of [Ru(N-N)3]2+ complexes.


      PubDate: 2014-06-18T16:38:55Z
       
  • Solid polymer and metallogel networks based on a fluorene derivative as
           fluorescent and colourimetric chemosensors for Hg(II)
    • Abstract: Publication date: June 2014
      Source:Reactive and Functional Polymers, Volume 79
      Author(s): Jesús L. Pablos , Saturnino Ibeas , Asunción Muñoz , Felipe Serna , Félix C. García , José M. García
      This work describes two sensing systems for the detection and quantification of Hg(II): (a) a highly tractable solid polymer membrane, and (b) a gelling system based on a low molecular weight gelator. The preparation of both sensory systems relies on a polymerisable acrylic monomer derived from a fluorene core containing a functional hydroxyimino group, which at the same time is an organogelator with Hg(II)-triggered gelating properties in organic solution. The polymerisation of this monomer with commercial comonomers gave a cross-linked membrane or film, which permitted the detection of Hg(II) using UV/Vis and fluorescence techniques due to the colour and fluorescence changes in response to the interaction of the film with Hg(II). At the same time, organic solutions of the monomer – or gelator – gave a gel upon interacting with Hg(II). Engineering of the gel formation conditions permitted the tuning of the visual detection threshold of the concentration of Hg(II), which ranged from 6×10−3 to 1×10−2 M in our study, while the membrane permitted the detection by UV/Vis and fluorescence spectroscopy of Hg(II) in organic and organic/aqueous media in the millimolar–micromolar range. Furthermore, the colour and fluorescence changes of the two systems were clearly visible, allowing for the naked-eye detection and broad quantification of milli to micromolar concentrations of Hg(II).
      Graphical abstract image Highlights

      PubDate: 2014-04-29T14:18:10Z
       
  • A palladium-loaded mesoporous polymer monolith as reusable heterogeneous
           catalyst for cross-coupling reactions
    • Abstract: Publication date: June 2014
      Source:Reactive and Functional Polymers, Volume 79
      Author(s): Dhiman Kundu , Astam K. Patra , Junji Sakamoto , Hiroshi Uyama
      A new palladium catalyst based on a mesoporous polymer monolith has been introduced. A polyacrylonitrile (PAN) monolith prepared by a phase separation technique was used as precursor material for chemical modification; the nitrile groups on the monolith surface were transformed into amidine groups and then bound to palladium dichloride via coordination. A series of Suzuki–Miyaura cross-coupling reactions were successfully demonstrated by using the monolith as catalyst. Moreover, the monolith was found to exhibit excellent stability for repeated use.
      Graphical abstract image Highlights

      PubDate: 2014-04-29T14:18:10Z
       
  • Use of MALDI-ToF MS to elucidate the structure of oligomeric impurities
           formed during ‘click’ cyclization of polystyrene
    • Abstract: Publication date: Available online 12 February 2014
      Source:Reactive and Functional Polymers
      Author(s): Subramanya G. Sreerama , Ravinder Elupula , Boyd A. Laurent , Boyu Zhang , Scott M. Grayson
      Polymers with a cyclic topology exhibit a range of unique and potentially useful physical properties, including reduced rates of degradation and increased rates of diffusion in bulk relative to linear analogs. However, the synthesis of high purity cyclic polymers and verification of their structural purity remain challenging. The copper-catalyzed azide–alkyne “click” cyclization route toward cyclic polymers has been widely used, due to its synthetic ease and its compatibility with diverse polymer backbones. Yet unoptimized click cyclization conditions have been observed to generate oligomeric byproducts. In order to optimize these cyclization conditions, and to better understand the structure of the higher molecular weight oligomers, these impurities have been isolated and characterized. Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI–ToF) MS is a particularly valuable characterization tool and was used to determine that the high molecular weight impurities are predominantly cyclic oligomers. It should also be noted that the rapid analysis and small analyte requirements of this MS technique make it particularly attractive as a general tool for elucidating polymer architecture.


      PubDate: 2014-04-29T14:18:10Z
       
  • Editors and Editorial Board
    • Abstract: Publication date: May 2014
      Source:Reactive and Functional Polymers, Volume 78




      PubDate: 2014-04-29T14:18:10Z
       
  • Fabrication of polymer/ZnS nanoparticle composites by matrix-mediated
           synthesis
    • Abstract: Publication date: June 2014
      Source:Reactive and Functional Polymers, Volume 79
      Author(s): Tomonari Ogata , Norio Hirakawa , Yuuki Nakashima , Yutaka Kuwahara , Seiji Kurihara
      Zinc sulfide nanoparticles are obtained as primary particles in a polymer matrix by a matrix-mediated synthesis. Two types of matrix polymer are synthesized via the copolymerization of hydrophobic, cation-exchange, and cross-linking monomers. The ZnS nanoparticles are affected by the composition of the matrix polymer, and especially by its hydrophobicity. In a low-hydrophobicity copolymer matrix, aggregates of ZnS nanoparticles are observed in the matrix using transmission electron microscopy (TEM) and X-ray diffraction (XRD). In a high-hydrophobicity cation-exchange copolymer matrix, primary particles of ZnS with 2–5nm diameters are observed in the matrix by TEM. However, the ZnS pattern is not distinguishable in XRD measurements because the particle sizes are too small to diffract X-rays.


      PubDate: 2014-04-29T14:18:10Z
       
  • Hydrogel films engineered in a mesoscopically ordered structure and
           responsive to ethanol vapors
    • Abstract: Publication date: June 2014
      Source:Reactive and Functional Polymers, Volume 79
      Author(s): Clelia Dispenza , Maria Antonietta Sabatino , Sabina Alessi , Giuseppe Spadaro , Leonardo D’Acquisto , Riccardo Pernice , Gabriele Adamo , Salvatore Stivala , Antonino Parisi , Patrizia Livreri , Alessandro C. Busacca
      Responsive hydrogels filling the interstitial spaces of photonic crystals can form mesoscopically structured materials, which exhibit reversible shifts in the Bragg diffracted light as a response of environmental changes. These materials can be used to generate chemical or biochemical sensors. The present work reports on the synthesis and characterization of ethanol responsive hydrogels that can be used in the design of novel breathalyzers. The dynamic mechanical behavior of the macroscopic hydrogels and their swelling features in the presence of different liquids or vapors have been investigated to orientate the choice of the best responsive material and curing process. The swelling behavior of a selected hydrogel embedding the photonic crystal made of polystyrene nanoparticles as function of the concentration of ethanol vapor was studied through UV–Vis optical transmission spectroscopy and compared to the behavior of the macrogel analogue.


      PubDate: 2014-04-29T14:18:10Z
       
  • Cyclic polymers as a building block for cyclic brush polymers and gels
    • Abstract: Publication date: Available online 11 February 2014
      Source:Reactive and Functional Polymers
      Author(s): Ke Zhang , Gregory N. Tew
      Cyclic polymers, as one of the oldest topological polymers, are undergoing resurgence. This is largely ascribed to the significant achievements in modern polymer chemistry. The novel ring-expansion techniques have conveniently produced varied cyclic polymers with highly topological purity and on large scales, which should facilitate their use in the near future. Beyond the monocyclic molecular conformations, the combination of controlled polymerization techniques and click chemistry have established a robust strategy for preparing cyclic polymers with more complex architectures, such as theta, eight, and tadpole shapes. This diversification in cyclic polymer composition and conformation significantly broadens interest in the cyclic polymers. However, compared to the synthesis achievements, the exploration of cyclic polymer property and application are lagging behind. Recently, we explored the ring-expansion metathesis polymerization on various functional ring-strained olefin monomers to produce cyclic functional polymers, which were then used as the building blocks to fabricate cyclic brush polymers and cyclic gel materials and will be discussed here.


      PubDate: 2014-04-29T14:18:10Z
       
  • Dynamic, conformational and topological properties of ring–linear
           poly(ethylene oxide) blends from molecular dynamics simulations
    • Abstract: Publication date: Available online 11 February 2014
      Source:Reactive and Functional Polymers
      Author(s): Dimitrios G. Tsalikis , Thanasis Koukoulas , Vlasis G. Mavrantzas
      We present results for the equilibrium conformational and dynamic properties of ring–linear poly(ethylene oxide) (PEO) blends from detailed molecular dynamics (MD) simulations with a thoroughly validated and very accurate forcefield. The simulations have been performed in the isothermal–isobaric (NPT) statistical ensemble with blends where the two types of chains (ring and linear) have the same size. Simulations with two different chain lengths, corresponding to molecular weights equal to 1800 and 5000g/mol, allowed us to study the dependence of these properties on molecular length. Overall, the presence of linear chains seems to considerably slow down the orientational relaxation of ring molecules and to lower their diffusivity, to a degree that depends strongly on chain length and level of contamination of the melt by linear chains. The longer the size of the molecules the more pronounced the decrease in ring diffusivity is, at a given mass fraction of linear chains. To explain the reduction in the relaxation and mobility of ring molecules when they mix with linear chains to form a blend, selected configurations from the MD simulations were subjected to a detailed topological analysis which revealed significant threading of the cyclic molecules by the linear ones. Our simulation data indicate that, due to threading, ring dynamics in ring–linear PEO melts is strongly heterogeneous. An analysis of the statistics of the lifetimes of ring–linear topological constraints (TCs) reveals a long tail on the long time scale, demonstrating that many of these TCs are long-lived. By inspecting individual ring–linear PEO pairs we found that, in many cases, the lifetimes of these TCs are up to one order of magnitude larger than the typical time characterizing ring relaxation in the pure ring melt. This phenomenon was more pronounced in the blend with the longer molecules (molecular weight=5000g/mol).


      PubDate: 2014-04-29T14:18:10Z
       
  • Poly(ionic liquid)s with redox active counter-anions: All-in-one reactants
           and stabilizers for the synthesis of functional colloids
    • Abstract: Publication date: June 2014
      Source:Reactive and Functional Polymers, Volume 79
      Author(s): Raquel Gracia , Kari Vijayakrishna , David Mecerreyes
      A family of all-in-one redox reactants and polymeric stabilizer or surfactant for the synthesis of functional colloids has been developed. For this purpose, poly(ionic liquid)s with cationic imidazolium or pyrrolidonium backbones and redox active counter-anions such as ReO4 −, WO4 2 −, S2O4 2 −, S2O8 2 −, NO3 −, BH3CN− were synthesized. Poly(1-vinyl-3-ethylimidazolium) with BH3CN− reducing counter-anion have been used in order to synthesize silver and gold nanoparticles aqueous dispersions of 150–180nm and ∼20nm respectively. On the other hand, poly(dimethyldiallylammonium) with S2O8 2 − oxidizing counter-anion is used to obtain PEDOT dispersions and a conventional acrylic polymer latex.
      Graphical abstract image Highlights

      PubDate: 2014-04-29T14:18:10Z
       
  • Mean-square radius of gyration and hydrodynamic radius for topological
           polymers evaluated through the quaternionic algorithm
    • Abstract: Publication date: Available online 19 March 2014
      Source:Reactive and Functional Polymers
      Author(s): Erica Uehara , Ryota Tanaka , Mizue Inoue , Fukiko Hirose , Tetsuo Deguchi
      We evaluate numerically the mean-square (MS) radius of gyration and the diffusion coefficient for topological polymers such as ring, tadpole, double-ring, and caged polymers and catenanes. We consider caged polymers with any given number of subchains, and catenanes consisting of two linked ring polymers with a fixed linking number. Through Kirkwood’s approximation we evaluate the hydrodynamic radius, which is proportional to the inverse of the diffusion coefficient, for various topological polymers. Here we take the statistical averages over configurations of topological polymers constructed through the quaternionic algorithm, which generates uniform random walks connecting given two points. It gives ideal chains with no excluded volume. We evaluate numerically the ratio of the square root of the MS radius of gyration to the hydrodynamic radius for several topological polymers, and show for them that the ratio decreases as the topology becomes more complex.


      PubDate: 2014-04-29T14:18:10Z
       
  • Cyclic poly(vinylcarbazole) via ring-expansion polymerization-RAFT
           (REP-RAFT)
    • Abstract: Publication date: Available online 20 March 2014
      Source:Reactive and Functional Polymers
      Author(s): Ajaykumar Bunha , Peng-Fei Cao , Joey Dacula Mangadlao , Rigoberto C. Advincula
      In this paper, we demonstrate the formation of cyclic poly(vinylcarbazole) via a ring-expansion polymerization reversible addition-fragmentation chain transfer (REP-RAFT). A cyclic dixanthate RAFT chain transfer agent (CTA) was synthesized and employed for controlled free radical polymerization of N-vinylcarbazole (NVK). The molecular weight in relation to polymerization time suggested the formation of a polymer with well-controlled molecular weight and ring size. The obtained macromolecules were characterized by nuclear magnetic resonance (NMR), X-ray photoelectron spectroscopy (XPS) and dynamic light scattering (DLS). Atomic force microscopy (AFM) was also employed to directly observe the cyclic polymers with different ring sizes.


      PubDate: 2014-04-29T14:18:10Z
       
  • Water-soluble polyaniline/graphene prepared by in situ polymerization in
           graphene dispersions and use as counter-electrode materials for
           dye-sensitized solar cells
    • Abstract: Publication date: June 2014
      Source:Reactive and Functional Polymers, Volume 79
      Author(s): Li Wan , Bi Wang , Shimin Wang , Xianbao Wang , Zhiguang Guo , Huayu Xiong , Binghai Dong , Li Zhao , Hongbing Lu , Zuxun Xu , Xiuhua Zhang , Taiping Li , Wen Zhou
      Water-soluble polyaniline/graphene nanocomposites have been prepared via a simple in situ polymerization of aniline in graphene dispersion. TEM measurement confirmed that polyaniline was homogeneously coated on the graphene sheets. The nanocomposites solution can be used for film fabrication by common technology, such as drop coating. When these different polyaniline/graphene nanocomposites were applied as the counter electrode materials for dye-sensitized solar cells, the short-circuit current density and power-conversion efficiency of the devices were measured to be 12.19mAcm−2 and 4.46%, respectively, which was comparable to 5.71% for the cell with a Pt counter electrode under the same experimental conditions.


      PubDate: 2014-04-29T14:18:10Z
       
  • Special issue ‘Cyclic polymers: New developments’
    • Abstract: Publication date: Available online 2 April 2014
      Source:Reactive and Functional Polymers
      Author(s): Scott M. Grayson , Yutan Getzler , Donghui Zhang



      PubDate: 2014-04-29T14:18:10Z
       
  • Synthesis of NIPAAm-based polymer-grafted silica beads by
           surface-initiated ATRP using Me4Cyclam ligands and the thermo-responsive
           behaviors for lanthanide(III) ions
    • Abstract: Publication date: June 2014
      Source:Reactive and Functional Polymers, Volume 79
      Author(s): Ki Chul Park , Naokazu Idota , Takehiko Tsukahara
      The applicability of atom transfer radical polymerization (ATRP) to the copolymerization of N-isopropylacrylamide (NIPAAm) with N-vinyl-2-pyrrolidone (NVP) was examined in CuCl/CuCl2-catalyst system using tris[2-(dimethylamino)ethyl]amine (Me6TREN) and 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane (Me4Cyclam) as ligands. In the Me6TREN system, less reactive NVP not only does not quantitatively copolymerize but also interferes with homopolymerization of NIPAAm units. In contrast, the Me4Cyclam system under heating was more active, although the controllability for polymer homogeneity is lower than Me6TREN system. The application of active Me4Cyclam system to surface-initiated ATRP has successfully prepared silica beads surface-modified with NIPAAm copolymers of NVP and 4-vinylpyridine (VPy). The thermo-responsive behavior of surface-grafted NIPAAm-based polymers was investigated for lanthanide trivalent ions (Ln(III)) in different pH solutions. In the weak acidic solutions of pH=5.4–5.6, all the surface-grafted polymers including poly(NIPAAm) exhibited only adsorption behavior with regular selectivity (Eu3+ >Sm3+ >Nd3+ >Ce3+ >La3+) below the phase-transition temperatures. In the more acidic solution of pH=2.9, the surface-grafted poly(NIPAAm) and NVP copolymers exhibited adsorption and desorption behaviors below and above the phase-transition temperatures, while VPy copolymers exhibited only adsorption independent of temperature change. Furthermore, the adsorption capacity of all the surface-grafted polymers was deteriorated by the lowering of pH. The observed desorption and the deterioration of adsorption capacity suggest the weakening of adsorption strength for Ln(III) in low pH solutions. In this study, a possible adsorption/desorption mechanism of Ln(III) on surface-grafted NIPAAm-based polymers is discussed.


      PubDate: 2014-04-29T14:18:10Z
       
  • Thermal conductivity of graphene nanoribbons with defects and nitrogen
           doping
    • Abstract: Publication date: June 2014
      Source:Reactive and Functional Polymers, Volume 79
      Author(s): Haiying Yang , Yunqing Tang , Yu Liu , Xingang Yu , Ping Yang
      Thermal conductivity of defective graphene nanoribbons doped with nitrogen for different distributions around the defect edge at nanoscale is investigated using the reverse non-equilibrium molecular dynamics (RNEMD) method, which explores ways to improve thermal management. In addition, thermal conductivity of graphene nanoribbons with both defects and nearby nitrogen doping is investigated in comparison to that of nanoribbons with defects alone. The simulation results are analyzed from three perspectives: phonon match, concentration of N doping, and distribution of N doping. This approach reveals that a coupling effect is the cause of the observed results. Nitrogen doped graphene nanoribbons (both perfect and defective variants) perform better with thermal management than do graphene nanoribbons with defects alone, which is of considerable interest. Based on these investigations, a guide for graphene-interconnected circuits design is implied.


      PubDate: 2014-04-29T14:18:10Z
       
  • Multidimensional mass spectrometry methods for the structural
           characterization of cyclic polymers
    • Abstract: Publication date: Available online 3 April 2014
      Source:Reactive and Functional Polymers
      Author(s): Aleer M. Yol , Chrys Wesdemiotis
      Several synthetic methods have been developed for the tailored preparation of cyclic macromolecules due to their unique physical and chemical properties. Unequivocal characterization of the macrocyclic architectures has remained challenging, however, because isomeric linear structures often exist, or the spectral features of linear vs. cyclic chains are similar. To address this problem, multidimensional mass spectrometry (MS) techniques have been evaluated for the separation and identification of polymeric macrocycles. Tandem mass spectrometry (MS2) is found to be ideally suitable for the differentiation of linear and cyclic architectures whose molecular ions exhibit distinct fragmentation characteristics. Conversely, differences in macromolecular sizes and shapes can be exploited to identify the correct architecture by ion mobility mass spectrometry (IM-MS). A third option, chromatographic separation (LC) before MS analysis, is available for the detection of cyclics in complex mixtures. The capabilities of these techniques and combinations thereof are demonstrated with specific covalent or supramolecular (co)polymers.
      Graphical abstract image Highlights

      PubDate: 2014-04-29T14:18:10Z
       
  • Poly(N,N-dimethylaminoethyl methacrylate)/graphene oxide hybrid hydrogels:
           pH and temperature sensitivities and Cr(VI) adsorption
    • Abstract: Publication date: Available online 12 April 2014
      Source:Reactive and Functional Polymers
      Author(s): Jianquan Wang , Danqiao Song , Shanshan Jia , Ziqiang Shao
      Different amounts of graphene oxide (GO) were incorporated to N,N-dimethylaminoethyl methacrylate (DMAEMA), fabricating a series of pH and temperature dual sensitive PDMAEMA/GO hybrid hydrogels by in situ polymerization. Their microscopic network structures as well as swelling properties and Cr(VI) adsorption were characterized. The equilibrium swelling ratios (ESR) of hydrogels increased significantly with 0.5 wt% GO feeding of DMAEMA amount, and then decreased with further GO loading increasing. All hydrogels showed obvious deswelling when pH value of swelling mediums increased from 5 to 10 gradually. At pH 7, hydrogels revealed slight ESR increment with temperature up to 50 °C, above which obvious deswelling occurred. In pH 8 buffer, 0.5 wt% of GO loading triggered lower critical solution temperature (LCST) to decrease by 3 °C, and 2-7 °C increment was observed when 1-6 wt% of GO was loaded, as compared with that of GO-free PDMAEMA hydrogel. Cr(VI) adsorption of hydrogels was also improved by the introduction of GO to some extent,and the maximum Cr(VI) adsorption of 180 mg/g was realized, indicating that the obtained PDMAEMA/GO hybrid hydrogels possess excellent adsorption performance.


      PubDate: 2014-04-29T14:18:10Z
       
  • Editors and Editorial Board
    • Abstract: Publication date: June 2014
      Source:Reactive and Functional Polymers, Volume 79




      PubDate: 2014-04-29T14:18:10Z
       
  • ECTFE membrane preparation for recovery of humidified gas streams using
           membrane condenser
    • Abstract: Publication date: June 2014
      Source:Reactive and Functional Polymers, Volume 79
      Author(s): E. Drioli , S. Santoro , S. Simone , G. Barbieri , A. Brunetti , F. Macedonio , A. Figoli
      Polymeric flat membranes, using Ethylene–Chlorotrifluoroethylene copolymer (ECTFE), have been made by Thermal Induced Phase Inversion (TIPS). The non-toxic solvent glycerol triacetate (GTA) has been used as solvent. The morphology of the membranes has been analyzed by scanning electron microscopy (SEM). Asymmetric microporous sponge-like membranes have been produced and their properties in terms of contact angle, mechanical properties, pore size and porosity have been compared with the commercial PVDF hollow-fibers membranes. Both types of membranes have been tested using a membrane condenser, varying the feed temperature and feed flow rate, for the selective recovery of water from gaseous streams. The data obtained have been also supported by a simulation study of the process. The results showed that in both type of polymers used, the percentage of water recovered was similar, between 35% and 55%, much higher than the amount of 20% needed to make the plant self-sufficient. The obtained results and the outstanding chemical resistance properties suggested that the ECTFE flat membranes are very promising candidates for being employed in a membrane condenser, which is a new membrane based operation for water recovery from gaseous waste streams (i.e. flue gas).


      PubDate: 2014-04-29T14:18:10Z
       
  • Immobilization of Rhodamine 6G in Calcium Alginate Microcapsules based on
           Aromatic-Aromatic Interactions with Poly(sodium 4-styrenesulfonate)
    • Abstract: Publication date: Available online 12 April 2014
      Source:Reactive and Functional Polymers
      Author(s): Esteban Araya-Hermosilla , Daniel Muñoz , Sandra Orellana , Alejandro Yáñez , Andrés F. Olea , Felipe Oyarzun-Ampuero , Ignacio Moreno-Villoslada
      Immobilization of rhodamine 6G in calcium alginate microcapsules was achieved using the polyanion bearing negatively charged aromatic groups poly(sodium 4-styrenesulfonate) as complexing agent. The immobilization of the dye by this method finds its basis on the stabilization of the dye / polymer complex by short-range aromatic-aromatic interactions, which are resistant to the cleaving effect of highly concentrated electrolytes. On the contrary, direct immobilization of the dye in the microcapsules resulted unsuccessful due to its high diffusion coefficient in the aqueous medium, and complexation with poly(sodium vinylsulfonate) did not improve the immobilization, since the corresponding complex is based on long-range electrostatic interactions, which are easily cleaved under the high ionic strength conditions of the microcapsule formation reaction. Thus, the present investigation represents a proof of concept on the use of aromatic-aromatic interactions between polyelectrolytes bearing charged aromatic rings and their aromatic counterions as a tool to achieve improved functionalities. The release of the rhodamine 6G / poly(sodium 4-styrenesulfonate) complex from the microcapsules has been investigated as a function of pH and temperature. Coating the microcapsules with chitosan allowed minimizing the release of the dye from the microcapsules.
      Graphical abstract image Highlights

      PubDate: 2014-04-29T14:18:10Z
       
  • Synthesis of thermally stable, wholly aromatic polyketones with
           2,2′-dimethoxy-1,1′-binaphthyl-6,6′-diyl units through
           nanosized-palladium-cluster-catalyzed Suzuki–Miyaura coupling
           polymerization
    • Abstract: Publication date: June 2014
      Source:Reactive and Functional Polymers, Volume 79
      Author(s): Katsuya Maeyama , Masanori Suzuki , Tadashi Tsukamoto , Shuhei Higashibayashi , Hidehiro Sakurai
      Wholly aromatic polyketones with 2,2′-dimethoxy-1,1′-binaphthyl-6,6′-diyl units in the main chains were synthesized through Suzuki–Miyaura coupling polymerization catalyzed by nanosized palladium clusters, which were easily prepared from Pd(OAc)2, PPh3, K2CO3, and Bu4NOAc in 1,4-dioxane. The resulting polyketones have both high thermal stability (high T g) and solubility in common organic solvents, such as CHCl3 and N,N-dimethylformamide (DMF). Flexible and pale brown films were obtained by casting from a CHCl3 solution.


      PubDate: 2014-04-29T14:18:10Z
       
  • Efficient RAFT polymerization of N-(3-aminopropyl)methacrylamide
           hydrochloride using unprotected “clickable” chain transfer
           agents
    • Abstract: Publication date: Available online 13 April 2014
      Source:Reactive and Functional Polymers
      Author(s): Patrícia V. Mendonça , Arménio C. Serra , Anatoliy V. Popov , Tamaz Guliashvili , Jorge F.J. Coelho
      The reversible addition fragmentation transfer (RAFT) of N-(3-aminopropyl)methacrylamide hydrochloride (APMA) using unprotected “clickable” chain transfer agents in water/dioxane mixtures is reported. The controlled character of the polymerization was confirmed by the linear increase in the polymer molecular weight with monomer conversion, the narrow molecular weight distribution (Ð ⩽ 1.1) and by chain extension experiments. The alkyne-terminated PAPMA was further functionalized by “click” chemistry with an azido-functionalized coumarin derivative. The method reported here will be useful for the preparation of novel PAPMA based materials for biomedical applications using a strategy that does not require challenging protection/deprotection steps.


      PubDate: 2014-04-29T14:18:10Z
       
  • Electrochemical Responsive Arrays of Sulfonatocalixarene Groups Prepared
           by Free Radical Polymerization
    • Abstract: Publication date: Available online 18 April 2014
      Source:Reactive and Functional Polymers
      Author(s): Uddhav Balami , Darlene K. Taylor
      A styrene based water soluble polymer containing pendant sulfonated calix[4]arene groups has been synthesized by using free radical polymerization combined with post-polymerization sulfonation chemistry. The monomer 25-(4-vinylbenzyl)-26, 27, 28-hydroxy-calix[4]arene (VBC4A) was prepared in 3 steps: 1) reduction of 4-vinyl benzoic acid to the respective alcohol 2) formation of the bromide by the Appel reaction and 3) synthesis of the respective ether by Williamson O-alkylation reaction with calix[4]arene. Polymerization was accomplished by azobisisobutyronitrile (AIBN) initiated free radical polymerization technique to afford P(VBC4A) with Mn value of 7090 g/mol and moderate polydispersity. The resulting P(VBC4A) was subsequently reacted with acetyl sulfate to afforded the sulfonated polymer. The reaction was followed by nuclear magnetic resonance and infrared spectroscopy, and the results suggest that the sulfonation reaction lead to nearly quantitative functionalization of the calixarene functional polymer. Elemental analysis by x-ray photoelectron spectroscopy confirmed these findings on the degree of sulfonated functionalization. Electro-responsive properties of the sulfonated polymer were studied by cyclic voltammetry and isothermal titration calorimetry in phosphate buffer saline solution. A response to electrochemical stimulus is observed where guest molecules of methyl viologen incorporate and dissociate with P(VBSC4A).


      PubDate: 2014-04-29T14:18:10Z
       
  • Ion-Conductive and Mechanical Properties of Polyether/Silica Thin Fiber
           Composite Electrolytes
    • Abstract: Publication date: Available online 29 April 2014
      Source:Reactive and Functional Polymers
      Author(s): Satoki Ishibe , Kodai Anzai , Jin Nakamura , Yuichi Konosu , Minoru Ashizawa , Hidetoshi Matsumoto , Yoichi Tominaga
      To enhance the ionic conductivity and mechanical strength of existing polymer electrolytes, we have composited a submicro-scaled non-calcined silica thin fiber (ncl-SiF) in a polyether electrolyte. Composite electrolytes were prepared using polyether and inorganic fillers, including 5 mol% of lithium bis-(trifluoromethane sulfonyl) imide (LiTFSI), and the ionic conductivity and mechanical strength were measured. The submicro-scaled ncl-SiF composite improved the conductivity of the electrolyte, with the highest conductivity exceeding 10-4 S/cm at 30 °C. The stress-strain curves showed significant increases in the Young’s modulus and the stress at break for the composite samples, and the highest value of the Young’s modulus exceeded that of the original 10-fold. Thus, we conclude that highly dispersive ncl-SiF is a highly suitable material for the improvement of ionic conductivity and mechanical strength.
      Graphical abstract image Highlights

      PubDate: 2014-04-29T14:18:10Z
       
  • Preparation of growth factor-loaded biodegradable matrices consisting of
           poly(depsipeptide-co-lactide) and cell growth on the matrices
    • Abstract: Publication date: Available online 29 April 2014
      Source:Reactive and Functional Polymers
      Author(s): Yuichi Ohya , Jun Matori , Tatsuro Ouchi
      Biodegradable films and sponges of poly(depsipeptide-co-lactide)s with two reactive side-chain groups, poly[(Glc-Asp)-co-LA] and poly[(Glc-Lys)-co-LA], were prepared with entrapped growth factors (bFGF, EGF, and NGF) or models for these growth factors (lysozyme, insulin and lactoferrin) based on their physicochemical similarities. These films and sponges were prepared to evaluate the potential utility of these copolymers as biodegradable scaffolds for tissue engineering. Sustained release of the model proteins from the biodegradable matrices was observed. The cell growth rates on the growth factor-loaded matrices were higher than on those without growth factors and were at the same level as with the addition of native growth factors. The effective differentiation of PC12 cells into nerve-like cells were observed on NGF-loaded copolymer film. These results indicate that the released growth factors maintained their activity and that these copolymers would be good candidates for scaffolds for tissue engineering.


      PubDate: 2014-04-29T14:18:10Z
       
  • Studying Structure-Property Relationships in Oligomeric Engineering
           
    • Abstract: Publication date: Available online 29 April 2014
      Source:Reactive and Functional Polymers
      Author(s): Ian Hamerton , Brendan J. Howlin , Sin-Yi C. Yeung
      The preparation of a series of oligomeric engineering thermoplastics (PS, PES, PEI and PAI) is reported. 1H and 13C NMR and FT-IR/ATR spectroscopic techniques are combined to determine the chemical structure of the synthetic polymers, which are produced in good yield and purity. GPC measurements show the weight average molecular weight (Mw) of the synthesised thermoplastics fall in the range 5454 – 33866 g mol-1 and display polydispersity indices in the range 1.33 – 1.82. Glass transition temperatures (Tg) values measured by DSC, occur between 107 – 257 °C and fall in the pattern PS < PES < PEI < PAI. Molecular simulation is used to probe the structure property relationships displayed by PS and PES and reproduces the elastic properties of PS well within the range of the literature; while the values of PES are less well reproduced. The simulated Tg values of both oligomers agree well with those obtained empirically using DSC.


      PubDate: 2014-04-29T14:18:10Z
       
 
 
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